The present invention relates to a cartridge unit for containing toner powder and adapted to a developer of a copying machine etc. to supply toner powder.
One type of conventional toner cartridges is shown in the Japanese Published Unexamined Utility Model Application No. S60-145452, whose structure is illustrated in FIG. 15A. The mouth of the toner cartridge 201 is closed by a seal member 202, and an extension of the seal member 202 is folded back. When the toner cartridge 201 is attached to a toner hopper 203, the end of the extension is hooked by a pin 204 provided near the entrance of the toner hopper 3, as shown in FIG. 15B. As the cartridge 201 is pushed down the entrance of the toner hopper 203, the seal member 202 is deprived from the mouth and the toner powder in the cartridge 201 falls down to the toner hopper 203.
Another example is shown in the Japanese Published Unexamined Utility Model Application No. S59-9364, whose structure is illustrated in FIG. 16A. In this case, the mouth of a toner cartridge 205 is sealed by a plug 208. The toner cartridge 205 is attached to the toner hopper 207 by a male screw 206 formed on the outside surface of the cartridge body and a female screw formed on the inside surface of the entrance of the toner hopper 207. On a shelf provided at a midway of the hopper entrance stands a thrust rod 209. As the cartridge body is screwed down the entrance of the hopper 207, the thrust rod 209 pushes up the plug 208 and opens the mouth.
In any case, once the seal of the mouth of conventional toner cartridges is broken, the seal cannot recover the mouth. One problem is that when the toner powder in the cartridge is finished and the cartridge is removed from the toner hopper, the mouth is open and the remnant powder scatters. Another problem is that an operator can easily break the seal member 202 or push the plug 208 outside the hopper 203, 207 by mistake. The problem is more serious in this case.